In a wireless communication system where mobile terminals can perform communication, such as WiMAX (Worldwide Interoperability for Microwave Access), large numbers of base stations are installed at various locations. Mobile terminals present in an area (cell) covered by a base station can perform communication with the base station that covers the area.
With the movement of a mobile terminal, a base station which is a communication partner of the mobile terminal changes. Upon the change of the base station, the mobile terminal simultaneously receives signals transmitted from two base stations (a serving base station and a target base station).
Hence, in order to smoothly perform base-station-to-base-station movement of the mobile terminal, inter-base-station synchronization where transmission timings coincide with each other between adjacent base stations needs to be ensured.
When inter-base-station synchronization is achieved, upon base-station-to-base-station movement of the mobile terminal, the mobile terminal can simultaneously receive signals transmitted from two base stations and thus base-station-to-base-station movement (handover) can be performed smoothly.
Here, for techniques for achieving timing synchronization between base stations, there is one described in, for example, Patent Document 1.
Patent Document 1 discloses a technique in which each base station receives a GPS signal from a GPS satellite and achieves timing synchronization based on the GPS signal.